I wasn't as sure about how "40k" these guys would look back when they were previewed but I think they ended up firing the aesthetic just right. Scrap tech, plenty of chaos, begging for some grim dark colorations.
Combination of Speed Paint and Contrast paint for the base coats, yeah.
Speed paints:
Ruddy Fur - for the fur
Broadsword Silver and Talos Bronze - for the metals
Fire Giant Orange - Eyes and Glow
Hardened Leather - Straps and Belts
Grin Black - Weapons